class PokeBattle_Battle
  # Legacy method that should stop being used.
  def pbGetOwner(battlerIndex)
    if opposes?(battlerIndex)
      if @opponent.is_a?(Array)
        return (battlerIndex==1) ? @opponent[0] : @opponent[1]
      else
        return @opponent
      end
    else
      if @player.is_a?(Array)
        return (battlerIndex==0) ? @player[0] : @player[1]
      else
        return @player
      end
    end
  end

  # Reborn method (the difference is that each element in "choices" is an array
  # in Essentials but just a number in Reborn)
  def pbStdDev(choices)
    sum = 0
    n   = 0
    choices.each do |c|
      sum += c
      n += 1
    end
    return 0 if n<2
    mean = sum.to_f/n.to_f
    varianceTimesN = 0
    for i in 0...choices.length
      next if choices[i]<=0
      deviation = choices[i].to_f-mean
      varianceTimesN += deviation*deviation
    end
    # Using population standard deviation
    # [(n-1) makes it a sample std dev, would be 0 with only 1 sample]
    return Math.sqrt(varianceTimesN/n)
  end

  ##############################################################################
  # Choose an action.
  ##############################################################################
  def pbDefaultChooseEnemyCommand(idxBattler)
    if !@battle.pbCanShowFightMenu?(idxBattler)
      return if pbEnemyShouldUseItem?(idxBattler)
#      return if pbEnemyShouldWithdraw?(idxBattler)   # Old Switching Method
      return if pbShouldSwitch?(idxBattler)
      return if @battle.pbAutoFightMenu(idxBattler)
      @battle.pbAutoChooseMove(idxBattler)
      return
    end
    pbBuildMoveScores(idxBattler)   # Grab the array of scores/targets before doing anything else
    return if pbShouldSwitch?(idxBattler)
#    return if pbEnemyShouldWithdraw?(idxBattler)   # Old Switching Method
    return if pbEnemyShouldUseItem?(idxBattler)
    return if @battle.pbAutoFightMenu(idxBattler)
    @battle.pbRegisterUltraBurst(idxBattler) if pbEnemyShouldUltraBurst?(idxBattler)
    @battle.pbRegisterMegaEvolution(idxBattler) if pbEnemyShouldMegaEvolve?(idxBattler)
    if pbEnemyShouldZMove?(idxBattler)
      return pbChooseEnemyZMove(idxBattler)
    end
    pbChooseMoves(idxBattler)
  end

  def pbChooseEnemyZMove(index)  #Put specific cases for trainers using status Z-Moves
    chosenmove=false
    chosenindex=-1
    attacker = @battlers[index]
    opponent=attacker.pbOppositeOpposing
    otheropp=opponent.pbPartner
    skill=pbGetOwner(attacker.index).skill || 0
    for i in 0..3
      move=@battlers[index].moves[i]
      if @battlers[index].pbCompatibleZMoveFromMove?(move)
        if move.id == (PBMoves::CONVERSION) ||  move.id == (PBMoves::SPLASH)
          pbRegisterZMove(index)
          pbRegisterMove(index,i,false)
          pbRegisterTarget(index,opponent.index)
          return
        end
        if !chosenmove
          chosenindex = i
          chosenmove=move
        else
          if move.basedamage>chosenmove.basedamage
            chosenindex=i
            chosenmove=move
          end
        end
      end
    end

    #oppeff1 = chosenmove.pbTypeModifier(chosenmove.type,attacker,opponent)
    oppeff1 = pbTypeModNoMessages(chosenmove.type,attacker,opponent,chosenmove,skill)
    #oppeff2 = chosenmove.pbTypeModifier(chosenmove.type,attacker,otheropp)
    oppeff2 = pbTypeModNoMessages(chosenmove.type,attacker,otheropp,chosenmove,skill)
    oppeff1 = 0 if opponent.hp<(opponent.totalhp/2.0).round
    oppeff1 = 0 if (opponent.effects[PBEffects::Substitute]>0 || opponent.effects[PBEffects::Disguise]) && attacker.item!=(PBItems::KOMMONIUMZ2)
    oppeff2 = 0 if otheropp.hp<(otheropp.totalhp/2.0).round
    oppeff2 = 0 if (otheropp.effects[PBEffects::Substitute]>0 || otheropp.effects[PBEffects::Disguise]) && attacker.item!=(PBItems::KOMMONIUMZ2)
    oppmult=0
    for i in 1..7 #iterates through all the stats
      oppmult+=opponent.stages[i] if opponent.stages[i]>0
    end
    othermult=0
    for i in 1..7
      othermult+=otheropp.stages[i] if otheropp.stages[i]>0
    end
    if (oppeff1<4) && ((oppeff2<4) || otheropp.hp==0)
      pbChooseMoves(index)
    elsif oppeff1>oppeff2
      pbRegisterZMove(index)
      pbRegisterMove(index,chosenindex,false)
      pbRegisterTarget(index,opponent.index)
    elsif oppeff1<oppeff2
      pbRegisterZMove(index)
      pbRegisterMove(index,chosenindex,false)
      pbRegisterTarget(index,otheropp.index)
    elsif oppeff1==oppeff2
      if oppmult > othermult
        pbRegisterZMove(index)
        pbRegisterMove(index,chosenindex,false)
        pbRegisterTarget(index,opponent.index)
      elsif oppmult < othermult
        pbRegisterZMove(index)
        pbRegisterMove(index,chosenindex,false)
        pbRegisterTarget(index,otheropp.index)
      else
        if otheropp.hp > opponent.hp
          pbRegisterZMove(index)
          pbRegisterMove(index,chosenindex,false)
          pbRegisterTarget(index,otheropp.index)
        else
          pbRegisterZMove(index)
          pbRegisterMove(index,chosenindex,false)
          pbRegisterTarget(index,opponent.index)
        end
      end
    end
  end

  #=============================================================================
  # Decide whether the opponent should Ultra Burst their Pokémon.
  #=============================================================================
  def pbEnemyShouldUltraBurst?(idxBattler)
    battler = @battlers[idxBattler]
    if pbCanUltraBurst?(idxBattler)   # Simple "always should if possible"
      PBDebug.log("[AI] #{battler.pbThis} (#{idxBattler}) will Ultra Burst")
      return true
    end
    return false
  end
end